Wine Fridge Power Board

[Agent24]

Re: Wine Fridge Power Board

budm, the capacitance of C16 is 0.97 uF, and it is rated at 1.0uF
The other large capacitors on the board:
C20 = 0.070 uF, rated at 0.1 uF (capacitor near fuse)
C15 = 118 uF (rated 120)
C12 = 123 uF (rated 120). These are the units mentioned by kenny123 and are "near" C16.

These caps have not been replaced, but appear to be "close" to their rated values. Is "close" good enough, or should they be exact..

Because of material variances and manufacturing process variances, not all components will be exactly the same. That is why they are specified with a tolerance value in percent, which shows how much the part may deviate from the marked value.

If your 0.1uF capacitor is rated at 10%, then it can be anywhere between 0.9uF and 1.1uF and still be considered OK. They do not have to be exact.

If a part is outside its specified tolerance, it's either bad quality, damaged\faulty, or has drifted with age. In all cases it should be replaced.

Last thought on TR1, I have tried "finding" it online, but the numbers on it "HEC0809/A EE-19" seem elusive. Any thoughts on what this might mean? I would replace it if I could find it. The only thing I have found is the attached data sheet for an "AEE19-3460", but I don't understand the specification enough to determine its step down ratio. I see that the 5th specification indicates that PRI:SEC = 1:1, but that doesn't make sense either. What would be the point of a 1 to 1 input to output ratio?

Finding replacements for SMPS transformers is hard as they are often custom designed for each supply. There are some exceptions though (yours might be a "standard" EE-19 (Don't quote me on that!) but in any case, the transformers practically never fail, so it's not the first part to suspect as faulty by any stretch - unless it's visibly damaged.

A transformer with a 1:1 ratio would be used for isolation\coupling. Some SMPS designs might use a 1:1 transformer for part of a feedback loop for example.

The chip marked IC3 has no markings on it and my guess is that it proprietary.

Could be, but often they use standard parts and scrape the numbers off so you don't know what they used, so you can't copy the design (or realise they've ripped yours off!)

[keeney123]

Re: Wine Fridge Power Board

Originally Posted by acornish
The chip marked IC3 has no markings on it and my guess is that it proprietary.

You can usually tell what it is as to what it is connected to. Many times to safe guard a design manufacturers will wipe off the chip name and number. I have seen it done on programmed chips. This chip could be program one time chip to behave a certain way, that is only speculation though.

Also, I did use a roller to paint. The roller made a bigger mess then the brush that I used for the trim. This was paint the Manager of the apartment gave me. They use this on all the apartments. The paint I put on several years ago was good quality paint. Yes Dr. Kriesler was a good teacher and he was Head of the Department and Head of Graduate Emissions. He would work from 6:30 AM til past 9:00 PM He was in the applied Physics side.

[keeney123]

Re: Wine Fridge Power Board

BudM I notice something at little different in your component layout. I have adjusted the exposure and circled the area in question. To me it seems where you have a resistor there is a diode. That would be the resistor going back to the line . The other thing I noticed is the resistor I have circled does not appear in your component layout.

[budm]

Re: Wine Fridge Power Board

Yes, that one looks like it has shrink tubing on it (with Dxx printing next to it) and is connected between incoming AC L and another end goes to the junction of those two filter cap not to the primary DC negative as I have drawn. The resistor next to it looks to be connected between the circuit GND and the junction of the two filter caps.
Your brightened picture shows a lot better than the original

[budm]

Re: Wine Fridge Power Board

Sure like to know what that part is inside that tubing, and the Value of that resistor.

[keeney123]

Re: Wine Fridge Power Board

I made it a diode because it had Dxx on it. You also,missed R36. You had circled the end points of it, but you didn't put symbol in. This is a schematic Primary side with the correct component numbers as the board. I put the two components in that were in question to what I believe you referred to. I can values of resistors from what I can see. If you think something is wrong let me know. I will try and look up the transformers later on to get the correct pin number and voltage value. I found they usually go by the part number so if there is a ll-19 it usually means 19 volts.

[keeney123]

Re: Wine Fridge Power Board

acornish if you pull off the quality control sticker from the transformer I circled in white we could find out what number it is. Also if you could try and clean the top of the ICs. first try some water, lightly. Then use at least a time 5 Diopter magnifier to look at the chip numbers. If that does not work use some isopropyl alcohol. Let me know what numbers you come up with.

[keeney123]

Re: Wine Fridge Power Board

I believe the IC's are op amp LM358P, PulseWidth Modulator AZ494AP-E1. The input line Transformer that is being used as a inductor is either ET-24 or EE-25 both GP brand. The two big electrolytic caps are 330UF. The cap across the line and neutral is possibly 0.22 uF at 275 Volts. C16 is a 1uF 20% tolerance 200 volt. The big transformer is a ERL-28. Perhaps acornish can look at the board and confirm and possible add the voltage of the big caps. Once this is done I will continue to look up parts and draw rest of schematic

[dunkel]

Re: Wine Fridge Power Board

Hello, I am having problems with this board, some components are totally burnt and i would like to know the specs of them, can you guys help me? the components are:

L1
R34
R35
R36
D10

Thanks in advance

[fzabkar]

Re: Wine Fridge Power Board

Sure like to know what that part is inside that tubing ...

It appears to be a wire link that programs the fridge for 120VAC operation. Removing the link would configure it for 240VAC.

[keeney123]

Re: Wine Fridge Power Board

So the best spec. I can come up with is in post 106 schematic I drew up. I do not have the board, I am going from a picture. I tried to have the numbers verified by the person who has the board, but he has not responded back yet.

[fzabkar]

Re: Wine Fridge Power Board

Hello, I am having problems with this board, some components are totally burnt and i would like to know the specs of them, can you guys help me? the components are:

L1
R34
R35
R36
D10

I think that there may be errors in the hand drawn circuit diagram, but ISTM that there is enough symmetry in the circuit to enable the values of some of the damaged components to be inferred from other components.

R35 = R38
R34 = R37
D10 = D12

[keeney123]

Re: Wine Fridge Power Board

Yes dunkel the values possible could be in error as the color coding could be different from looking at a picture as apposed to seeing in real life. I Believe the schematic drawing to be very accurate. This can be confirmed by ohming out the various points on the board. As fzabkar said there is a symmetry of the circuit so some of the components are the same because you have two circuit performing similar functions. I would still lift these components up on one side and measure them as I have run across color codes that were wrong for the value of the part and yet the part was of the correct value. I think in China if they catch that the color code is wrong they go ahead and use the part because the part is good.

[fzabkar]

Re: Wine Fridge Power Board

My eyesight isn't young anymore, and I don't mean to nitpick an excellent body of work, but ISTM that, on the basis of symmetry alone, the network consisting of D10, R34, C13 and the associated transformer winding should terminate at the source of T7 rather than B-. Also the "DIODE" in parallel with D14 is clearly in error.

Edit: maybe R36 = R39

[keeney123]

Re: Wine Fridge Power Board

Fzabkar I do not mind the knit picking that is how something is proving. If you look at previous posts this board was from a unit not working correctly. It was the same as the board that was set up. My belief was that the D10 and C13 of this bad board are in backwards as are D14 and C14 and that is why it did not work. The person that has this board never got back to me. Perhaps the dunkel can confirm the direction of these components. The layout was from a virtual program from BudM all I did was develop a schematic from it. Do you have a schematic of this board or have you repaired these board? Also D14 is there, but it was listed as a resistor by BudM. I just put D14 because it had a marking of Dxx. Which I did not know what that meant perhaps you understand that marking?

[fzabkar]

Re: Wine Fridge Power Board

I don't know the reason for the Dxx circuit reference, but, as budm explains in post #104, it "is connected between incoming AC L and another end goes to the junction of those two filter cap not to the primary DC negative as I have drawn". This means that "it appears to be a wire link that programs the fridge for 120VAC operation", as I explained in post #110.

As for the polarities of D10/C13 and D14/C14, I'm still trying to get my head around it. ISTM that the diodes may be reversed, but I'm not certain.

[keeney123]

Re: Wine Fridge Power Board

fzabkar I have corrected it here. When BudM told me that I did not understand as he drew it to DC primary ground and indeed from the picture of the board it actually seems to go to the DC primary ground.

Also remember you are looking at 1/2 of the circuit. So there is feed back to control duty cycle and to turn off the devices it is controlling. These diodes and caps I believe are used for oscillation for the pulsated DC supply.

[budm]

Re: Wine Fridge Power Board

I wish I have the board in front of me, at first thought I was thinking it is set up as the Voltage Doubler circuit for 120AC line but looking at the connections it does not look right.
So the diode (the one connected to the two main filter cap +/- connection) as shown in the drawing is actually a jumper wire? It has to be for it to be Voltage Doubler circuit.
https://en.wikipedia.org/wiki/Rectif..._rectifier.svg

[keeney123]

Re: Wine Fridge Power Board

I wish I have the board in front of me, at first thought I was thinking it is set up as the Voltage Doubler circuit for 120AC line but looking at the connections it does not look right.
So the diode (the one connected to the two main filter cap +/- connection) as shown in the drawing is actually a jumper wire? It has to be for it to be Voltage Doubler circuit.
https://en.wikipedia.org/wiki/Rectif..._rectifier.svg

So here is the update primary side per your recommendations

[budm]

Re: Wine Fridge Power Board

I think the main power supply is OK, it is the switching circuit that is not working.